Optical communications links often require optical wavelength alignment within a specified grid. For this purpose, bulk-optic or fiber-coupled single-etalon external wavelength lockers have been used to provide a wavelength reference; however, these external lockers tend to be expensive, have large volumes (e.g., greater than 100 mm3), and limit the architecture of the PIC. Integrated wavelength lockers fabricated on-chip at the wafer-scale are highly desirable as they require less volume, can be fabricated with the other integrated photonic components at low cost in high volume, and enable functional architectures for the PIC that are more power efficient. The performance of conventional integrated wavelength lockers is, however, insufficient for many products. Fabrication variations, for example, can decrease the locking sensitivity and/or its predictability, and temperature fluctuations and strains imposed post-fabrication can reduce the locking accuracy.